This concerns a casing placed around a stator and more specifically in front of a bladed zone of a rotor surrounding the stator, that is in front of a compressor or turbine section in the machine, and is used to stop the blade or rotor pieces fragments which would be projected towards it under the action of centrifugal force following a rupture due to an accident.
The U.S. Pat. No. 4,452,563 describes a shield formed of a continuous network of fibrous strips draped on the outer face of the stator opposite the rotor. This design seems relatively ineffective as the fibers would tear quite easily and accordingly not provide sufficient protection. Honeycombed layers of material could also be placed on said outer surface of the rotor, but, despite the increase of energy absorption offered by such a structure to slow down or stop the projectiles, this absorption would be localized where the impact occurs and the shield would also in this instance be quite easily transpierced. The European patent 0 626 502 describes a shield formed of plates placed side by side but having the same drawbacks.
Finally, the French patent 2 375 443 describes a continuous ring shield which breaks its fasteners when a detached blade strikes it. But the shield can be used as a lining to the stator or replace it and it can only the absorb kinetic energy of the blade by taking on a rotating movement. It is unable to absorb the energy, as in the invention, on warping as there is not enough surrounding space to warp it; finally, it is only effective if the imparted energy is sufficient to break all the fasteners, which limits its possibilities in use.